Fluid heat exchange apparatus



July 14, 1942. H. J. KERR FLUID HEAT EXCHANGE APPARATUS Filed April 50,1 938 5 Sheets-Sheet l INVENTOR. Howard J Kerr ATTQRNEY.

3 Sheets-Sheet 2 July 14, 1942. H. J. KERR FLUID HEAT EXCHANGE APPARATUSFiled April 30, 1938 INVENTOR. Howard J Kerr ATTORNEY.

July 14, 1942. H. J. KERR FLUID HEAT EXCHANGE APPARATUS 3 Sheets-Sheet 3Filed April so, 1938 Fig OOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOO8900000000000 OOOOQOOOOOOQOOOOOOOOO 0O00000000OOOOOOOOOOOOOO0000000000002 oounaoaaooou 00 caonooocacoo 8 .oonoeeooooaao INVENTOR. Howard J Keri"E l AT'fORNEY.

Patented July 14, 1942 UNITED STATE 2,289,969 FLUID HEAT EXCHANGEAPPARATUS Howard J.-Kerr, Westfleld, N. J.,

Babcock a Wilcox Company,

assignor to The Newark, N. 3., a

corporation of New Jersey Application April 30, 1938, Serial No. 205,229

90laims'.

This invention relates to fluid heat exchange apparatus, and it isexemplified in improvements in water tube steam boilers whereby the safesteaming capacities of such boilers are increased.

In the art of steam generation progressively" greater efllcieneieshavebeen attained by the utilization of higher operating pressures.Progressively higher rates of steam generation have also been a factorin the development of the art. Both factors have demonstrated theimportance of securing eflicient steam and water separation withoutincreasing the steam and water separating space in the drums. If thisspace were increased in accordance with prior art teachings, greaterdrum diameters would be necessary and, for the pertinent high pressures(of the order of 1000-2000 lbs. per sq. inch) the provision of drums ofthe necessarily greater diameter would result in excessive increases indrum wall thickness. They would be excessive from many standpointsincluding manufacturing limitations and cost-limitations. The presentinvention provides improvements which effect a safe degree of steam andwater separation at high pressures and high capacity operation withoutnecessitating drums of excessive diameter.

The high capacities of modern steam boilers have also made itparticularly diillcult to insure continuous supply of dry steam withoutexcessive drum capacity. The high heat input into the furnace wall tubesunder such high capacity conditions causes those tubes to produce highvelocity discharges of steam and water into the drum, and the naturaltendency of this condition is to keep the steam and water mixed withinthe drum. Furthermore, the necessity of providing adequate ligaments inthe drum prevents the concentration of the drum connections for suchfurnace wall tubes. They must be distributed over wide drum areas. Thisalso has an additional tendency to produce high drum turbulence and makesteam and water separation increasingly diflicult. The present inventionovercomes these difficulties, and, in so doing, utilizes the highvelocity of the discharges into the drum to promote steam and waterseparation and render a given boiler capable of supplying dry steamwhile operating at water levels higher than would otherwise bepermissible.

The present invention also provides a means for increasing the safesteaming capacity or a natural circulation steam boiler by minimizingthe amount of steam carried down with the water from the drum to thesteam generating tubes, and by increasing the amount of water receivedby them, through an increase in the boiler circulation rate.

Another object of the invention is to provide improvements which willenable a given water tube steam boiler- 'to operate at maximumcapacities by permitting effective operation of the boiler under highwater level conditions. To accomplish these results, the inventioncontemplates the use or centrifugal water and steam separators havingwhirl chambers each of which is provided with an exit for the separatedwater limited to the region of the perimeter of the chamber, preferablytangentially. Other objects of the invention will appear as thefollowing description proceeds.

The invention will be described with reference to the accompanyingdrawings in which certain embodiments of the invention are illustrated.

In the drawings:

Fig. 1 is a vertical section through a threedrum boiler of the bent-tubetype, constructed in accordance with the teachings of the invention;

Fig. 2 is a vertical sectional view showing the front drum of the Fig. 1boiler on an enlarged scale;

Fig. 3 is a detailed sectional view indicating the construction of theillustrative steam and water separator. This view may be considered astaken on the line 3-3 of Fig. 4;

Fig. 4 is a sectional view of the separator taken along a plane atright-angles to the plane of Fig. 3 and on such a section-line as thatindicated at 0-4 of Fig. 3;

Fig. 5 is a vertical section taken upon the section-line 5-5 in Fig. 4and looking in the direction of thearrows;

Fig. 6 is a vertical section of a two-drum type of bent-tube boiler towhich the invention is applied in another manner;

Fig. 7 is a vertical section of the steam and water drum of the Fig. 6boiler, on an enlarged scale;

. Fig. 8 is a horizontal sectional view of the Fig. 1 boiler takenapproximately on the section-line 8-0 of Fi l; v

Fig. 9 is a horizontal section taken on the section-line 99 of Fig. 6;

Fig. 10 is a vertical section showing a modification of the structureindicated in Fig. 2.

Fig. l of the drawings discloses a bent-tube boiler having front andrear upper drums l0 and I2 connected with the submerged drum M by thebanks of tubes i6 and I8, respectively. The steam generating tubes ofthe tube bank l8 are exposed to the heat of the furnace 20, the furnacegases passing over these tubes.

Steam and water is discharged by the tubes l8 into the front drum l0,and water together with some steamfrom this drum passes through thelarge diameter circulators 22, and then across the rear drum I2 throughthe cross-over tubes 24 and 26 into the rear tubes 23 of the boiler.This arrangement permits the use of the pressure differential betweenthe drums l and I2 to establish the tubes 28 definitely as downcomers,and with the use of the centrifugal-separators 30 interposed in thecross-over tube connections, the discharge through the circulators 22 isrelieved of steam, and circulatory advantages are obtained because ofthe higher density of fluid in the tubes 28 over their full heights. Thedensity of the fluid in these tubes is here compared with the density ofthe fluid in the tubes l8.

It will be understood that there are a number of the circulators 22 anda corresponding number of the separators 30 disposed longitudinally ofthe drum I2. The construction of the separators is indicated in Figs. 3and 4 of the drawings. Each separator consists of a whirl chamber 32,operating independently of gravity to insure steam-free water in thedowncomers 28 and thereby'increase maximum safe boiler capacity. Thecross-over tube 24 is arranged tangentially to the whirl chamber 32 soas to set up a circular flow of water within that chamber. This fiow isindicated by the arrow 34 in Fig. 3. In the operation of the whirlchamber, the pressure of the water at its perimeter is substantiallygreater than the pressure in the center of the chamber, and the pressureof the water is sub stantially equivalent to the combined velocity ofthe steam and water entering that chamber from the inlet cross-over tube24. The pressure at the perimeter of the chamber is always greater thanthe pressure in the center.

The liquid or water outlet of each whirl chamber 32 is provided in thepresent instance by the cross-over tube 26 which is arranged at theperimeter of the whirl chamber and preferably tangentially of thatchamber. The latter arrangement is indicated in Fig. 3 of the drawings.The water in the whirl chamber outlet 26 will have a velocitysubstantially equal to the combined velocity of the vapor (or gas) thetangential entrance 24, whereby a pressure is developed in the waterequivalent to this velocity.

The delivery water separators pressure of such steam and may be utilizedto lift the water chamber 40, the delivery pressure will cause theseparated water to be delivered, or discharged, from the separating zoneagainst the resistance of the higher water level.

of this drum is above the 4 With reference to the steam and waterseparators 40, it is to be noted that they receive the restrictedstreams of steam and water mix.ures from the wall tubes 50 which arehighly heated by reason of their exposure to radiant heat from thefurnace 20. These wall tubes 50 are in communication with the risers 42through the upper wall tube header 52.

In the form of the centrifugal steam and water separator indicated inFigs. 3 and 4 of the drawings the whirl chamber is closed except for theabove mentioned steam and water inlet 24, the water outlet 26, and thesteam outlet 54. The latter is arranged centrally of the whirl chamberso that the steam may be discharged axially of that chamber. The steamoutlet 56 of the horizontally arranged separators 40 are similarlyaxially arranged.

The vertical baiile a higher percentage rators 30,

generating capacity.

' Fig. 10 shows an embodiment of the invention similar to that indicatedin Fig. 2, but having the water outlet connection 65 for the waterchamber 40 directly connected to and discharging into a downcomer asshown.

Steam vented from the separators 30 through the outlets 54 passes intothe steam space of the I2 and thence through the steam scrubbers ofitake64. From this ofitake it passes to a superheater 66, the relation of thesuperheater tubes to the remainder of the tubes of this boiler beingindicated in Fig. 8 of the drawings. The furnace gases pass over thesteam generating tubes [8 and then over the tubes of the superheater 66through the first gas pass 68 defined by the boiler setting wall 10 andthe baffle 12. In passing over some of the tubes of the bank l6 at theexit of the gas pass 68 the gases turn into the second gas pass 14, passback across the tubes l6, and then make a second turn through a thirdgas pass 16. The tubes in the last two gas passes are separated from thegas flow equalization chamber by a baffle 82 which is shown in sectionin Fig. 1 From the outlet of the gas pass 16 furnace gases may pass overan economizer, and thence to an air heater,

Fig. 7 shows the arrangement of the illustrative densifier or steam andwater separator 200 when used for primary separation of water and steamin the drum 202 of the type of boiler indicated in Figs. 6 and 9 of thedrawings. The water and steam mixture discharged into the drum from thesteam generating tubes 204, 206, and 208, as well as the remaining steamgenerating tubes, is confined to a space 2") on the 202, this spacebeing to a superheater the drawings at In the boiler illustrated inFigs. 6 and 9, furnace gases pass from the furnace ill across the steamgenerating tubes 2" in the first gas pass 232 and then around the rearedge of the bai'lle 234. The gases then pass forwardly over steamgenerating tubes 238 in the second gas pass 2". Beyond the tubes 23! thegases tum rearwardly of the bailie 240- and pass out of the boilerthrough the third gas pass 242.

What is claimed is:

1. In a water tube steam generator, a furnace, means forming a submergedwater chamber, a plurality of upper steam and water drums, steamgenerating tubes connecting the water chamber to said drums and exposedto the heat of the furnace gases, wall cooling tubes associated with awall of the furnace and arranged to discharge the steam and watermixture therefrom into one of said drums, whirl chamber densifying meanswithin one of the drums and having direct connection with the wallcooling tubes so as to act upon the steam and water mixture dischargedfrom the wall cooling tubes to separate thesteam and water of saidmixture, the densifying means having an outlet connection to dischargethe separated water in a confined stream to a'position beneath the waterlevel of that drum, said densifying means discharging its separatedsteam directly into the steam space of said drum, downcomer tubesconnecting the water space of a succeeding one of said drums with saidwater chamber, water circulators connecting the first of said drums tosaid succeeding drum, and crossover tubes so associated with thecirculators and downcomers that water may flow directly to saiddowncomers from said first mentioned drum, means connecting the steamspaces of the drums, and steam offtake means arranged on one of thedrums.

2. In a 3-drum steam generator of the bent tube type, a front upperdrum, a rear upper drum, a steam outlet from the rear drum, meansforming a lower water chamber, downcomers and steam generating tubesconnecting said water chamber to said drums and extending across thepath of furnace gases, steam circulators connecting the front and rearupper drums, means forming a circular whirl chamber of a steam and waterseparator disposed within the rear drum,

means for conducting steam and water directly from the front drum to atangentially arranged inlet of the whirl chamber, and a direct connec-,

tion between a downcomer inlet and the water outlet of the whirl chamberconducting separated water in a confined stream from the whirl chamberto a downcomer, said whirl chamber being arranged with its steam outletin direct communication with the steam space of the rear drum.

3. In a steam generator, a furnace, a plurality of upper drums, a lowerdrum, front and rearward banks of tubes connecting the lower drum to theupper drums and disposed in the path of the furnace gases, a rearwardbank of tubes including downcomers, circulators connecting the upperdrums, the front bank of tubes discharging steam and water mixtures intothe front upper drum at high velocities by reason of the exposure ofthose tubes to furnace gases at high temperatures, means in a rearwardupper drum directly connecting tubes of a rearward bank with circulatorsconducting steam and water mixtures from the front drum, kinetic steamand water separators in said connecting means, the separators havingsteam outlets communicating with the steam space of the rearward drum,the

separated water passes from the separators in confined streams totheconnected downcomer tubes of the rearward bank, and a steam outlet insaid rearward drum.

4. In a steam generator, a steam and water drum normally having a waterlevel therein, a steam offtake leading from the steam space of the drum,means forming a cylindrically walled whirl chamber of a steam and waterseparator within the drum, said whirl chamber being disposed at least inpart above said level, steam generating tubes, steam and water inletmeans directing steam and water eccentrically or tangentially into thewhirl chamber at high velocity in such a way as to set up a whirlingaction of all of the steam and water in the whirl chamber, fluidconfining means establishing direct communication between the steamgenerating tubes and the steam and water inlet means, said whirl chamberhaving an interior wall which is unobstructed in line with the steam andwater inlet and at least to a position beyond the steam and water inlet,means including a restricted and liquid sealed whirl chamber outletproviding for the discharge of the separated water in a confined stream,outlet means beginning centrally of the end of the whirl chamber wherebyseparated steam may pass to the steam spac of the drum, and meansconnecting the water space of the drum to the inlets of the steamgenerating tubes, the whirl chamber and its outlet being constructed andarranged to cause water entering the chamber at the inlet to flowthrough the outlet with a velocity head sufficient at least to balancethe static head of the water in the drum when the drum water level ishigher than the level of the entrance of the outlet.

5. In a boiler having a steam and water drum and a plurality of steamgenerating tubes con nected to said drum, a centrifugal steam and waterseparator inside the drum and comprising a whirl chamber, a tangentialsteam and water inlet toward one end of said chamber, fluid confiningmeans establishing direct communication between the steam generatingtubes and the' whirl chamber inlet so that the whirl chamber saidchamber, said whirl chamber having an interior wall which isunobstructed in line with the steam and water inlet and at least to aposition beyond the steam and water inlet, a steam outlet at the end ofsaid chamber nearest the inlet, and a restricted water outlet at the endof said chamber opposite the steam outlet end, constructed and arrangedto cause water entering said chamber at said inlet to flow through saidoutlet with a velocity head sufficient at least to balance the statichead of the water in the drum when the drum water level is higher thanthe level of the entrance to said outlet.

6. In a boiler having a steam and water drum and a plurality of steamgenerating tubes connected to said drum, a centrifugal steam andstantially the pressure of the mixture leaving the tubes to cause awhirling of the fluid within said chamber, said whirl chamber having aninterior wall which is unobstructed in line with the steam and waterinlet and at least to a position beyond the steam and water inlet, asteam outlet at the end of said chamber nearest the inlet, and arestricted water outlet at the opposite end of said chamber, constructedand arranged to cause water entering said chamber at said inlet to flowthrough said outlet'with a substantial continuation of the velocity ofthe water within said chamber.

7. In a steam generator, a steam and water drum normally having a waterlevel therein, a steam offiake leading from the steam space of the drum,means forming a cylindrically walled whirl chamber of a steam and waterseparator within the drum, said whirl chamber being disposed at least inpart above said level, steam generating tubes, steam and water inletmeans directing steam and water eccentrically or tangentially into thewhirl chamber at high velocity in such a way as to set up a whirlingaction of all of the steam and water in the whirl chamber, fluidconfining means including a separate inlet compartment of the drumestablishing direct communication between the steam generating tubes andthe steam and water inlet means, said whirl chamber having an interiorwall which is unobstructed in line with the steam and water inlet and atleast to a position beyond the steam and water inlet, means including arestricted and liquid sealed whirl chamber outlet providing for thedischarge of the separated water in a confined stream, outlet meansbeginning centrally of th end of the whirl chamber whereby separatedsteam may pass to the steam space of the drum, and means connecting thewater space of the drum to the inlets of the steam generating tubes, thewhirl chamber and its outlet being constructed and arranged to causewater entering the chamber at the inlet to flow through the outlet witha velocity head sufficient at least to balance the static head of thewater in the drum when the drum water level is higher than the level ofthe entrance of the outlet, said inlet compartment communicating with.said inlet means on one side and having the steam generating tubesdischarging thereinto at its opposite side.

8. In a boiler having a steam and water drum and a plurality of steamgenerating tubes connected to said drum, a centrifugal steam and waterseparator including a whirl chamber inside the drum, a tangential steamand water inthe inlet, and a restricted steam outlet at the end lettoward one end of said chamber, fluid confining means including aseparate inlet compartment of the drum establishing direct communicationbetween the steam generating tubes and the whirl chamber inlet so thatthe whirl chamber receives the unseparated steam and water mixture fromthe steam generating tubes at substantially the pressure of the mixtureleaving the tubes to cause a whirling of the fluid within said chamber,said whirl chamber having an interior wall which is unobstructed in linewith the steam and water inlet and at least to a position beyond thesteam and water inlet, a steam outlet at the end of said chamber nearestwater outlet at the end of said chamber opposite the steam outlet end,constructed and arranged to cause water entering said chamber at saidinlet to flow through said outlet with a velociy head sufiicient atleast to balance the static head of the water in the drum when the drumwater level is higher than the level of the entrance to said outlet,said inlet compartment communicating wih the outlets of the steamgenerating tubes and having direct connection with said whirl chamberinlet.

9. In a boiler having a steam and water drum and a plurality of steamgenerating tubes connected to said drum, a centrifugal steam and waterseparator including a whirl chamber inside the drum, a tangential steamand water inlet toward one end of said chamber, fluid confining meansincluding a separate inlet compartment of the drum establishing directcommunication between the steam generating tubes and the whirl chamberinlet so that the whirl chamber receives the unseparated steam and watermixture from the steam generating tubes at substantially the pressure ofthe mixture leaving the tubes to cause a whirling of the fluid withinsaid chamber, said whirl chamber having an interior wall which isunobstructed in line with the steam and water inlet and at least to aposition beyond the steam and water inlet, a of said chamber nearest theinlet, and a restricted water outlet at the opposite end of saidchamber, constructed and arranged to cause water entering said chamberat said inlet to flow through said outlet with a substantialcontinuation of the velocity of the water within said chamber, saidinlet compartment communicating with the outlets of the steam generatingtubes and having direct communication with said whirl chamber inlet.

HOWARD J. KERR.

